diff --git a/libs/binder/ProcessState.cpp b/libs/binder/ProcessState.cpp
index ea61dc5..ce2cd99 100644
--- a/libs/binder/ProcessState.cpp
+++ b/libs/binder/ProcessState.cpp
@@ -385,6 +385,12 @@
     , mThreadPoolSeq(1)
     , mCallRestriction(CallRestriction::NONE)
 {
+
+// TODO(b/139016109): enforce in build system
+#if defined(__ANDROID_APEX__) && !defined(__ANDROID_APEX_COM_ANDROID_VNDK_CURRENT__)
+    LOG_ALWAYS_FATAL("Cannot use libbinder in APEX (only system.img libbinder) since it is not stable.");
+#endif
+
     if (mDriverFD >= 0) {
         // mmap the binder, providing a chunk of virtual address space to receive transactions.
         mVMStart = mmap(nullptr, BINDER_VM_SIZE, PROT_READ, MAP_PRIVATE | MAP_NORESERVE, mDriverFD, 0);